KR20160009024A - Cyanoacrylate compositions - Google Patents

Abstract

The present invention relates to a flexible cyanoacrylate-containing composition having improved torsional stress tolerance, particularly when bound to a plastic substrate.

Description

[0001] CYANOACRYLATE COMPOSITIONS [0002]

The present invention relates to a flexible cyanoacrylate-containing composition having improved torsional stress tolerance, particularly when bound to a plastic substrate.

Cyanoacrylate adhesive compositions are well known and widely used as fast curing instant adhesives with a wide variety of applications. 1990, Handbook of Adhesives , 27, 463-77, I. Skeist, ed., Van Nostrand Reinhold, New York, 3rd Ed. Please refer to. See also GH Millet, "Cyanoacrylate Adhesives" in Structural Adhesives: Chemistry and Technology , SR Hartshorn, ed., Plenun Press, New York, p. 249-307 (1986).

Cyanoacrylate compositions typically tend to cure to form polymeric materials that are relatively brittle. This is an undesirable property in certain applications where a certain degree of flexibility of the polymeric material is required. This application involves the binding of a flexible material, where it is desired that the flexibility of some degree of bonding and the flexibility of the material are matched. In applications where the polymeric material can be applied to various forces in its end-use application, flexible polymeric materials are preferred. For example, when two substrates are bonded together by a polymeric material, the substrate may not be held in an unstable state, but may be applied to an external force, for example, the substrate may form part of a moving object, And forms part of an immovable object that is applied to one or more continuous or intermittent forces derived from other moving objects.

In the past, there has been an effort to improve the flexibility of the cured product of the cyanoacrylate composition. For example, U.S. Pat. Reference will be made to patents 2,776,232, 2,784,215, 2,784,127, 3,699,127, 3,961,966, 4,364,876, and 4,444,933.

One way to overcome the brittleness of the polymerized cyanoacrylate adhesive was to plasticize the composition by using a monomer mixture. Using a mixture of cyanoacrylate monomers, it is believed that when the monomer mixture is cured, a more flexible polymeric material is produced. The second approach was to introduce the plasticizer into the cyanoacrylate composition. Where the flexibility is generally obtained at the cost of the cure rate and / or bond strength.

U.S.A. Patent No. 6,977,278 discloses a composition comprising (i) at least one lower cyanoacrylate monomer component selected from ethyl cyanoacrylate and methoxy cyanoacrylate; (ii) n-propyl-cyanoacrylate, iso-propyl cyanoacrylate, iso-propyl cyanoacrylate, and n-butyl acrylate in an amount of greater than 12 weight percent, based on the total weight of the combination of the lower cyanoacrylate monomer and the higher cyanoacrylate monomer. Butyl-cyanoacrylate, isobutyl-cyanoacrylate, tert-butyl-cyanoacrylate, n-pentyl-cyanoacrylate, 1-methyl- Acrylate, 1-ethyl-propyl-cyanoacrylate, neopentyl-cyanoacrylate, n-hexyl-cyanoacrylate, 1-methylpentyl-cyanoacrylate, octyl cyanoacrylate, n-octyl-cyanoacrylate, n-nonyl-cyanoacrylate, n-decyl-cyanoacrylate, n- Cyanoacrylate, benzyl-cyanoacrylate, phenyl-cyano Acrylate, tetrahydrofurfuryl-cyanoacrylate, allyl cyanoacrylate, propargyl-cyanoacrylate, 2-butenyl-cyanoacrylate, phenethyl-cyanoacrylate, chloropropyl-cyano Acrylate, isobutyl acrylate, nonyl acrylate, ethoxyethyl-cyanoacrylate, ethoxypropyl-cyanoacrylate, ethoxyisopropyl-cyanoacrylate, propoxyethyl-cyanoacrylate, isopropoxyethyl- , Methoxypropyl-cyanoacrylate, methoxyethyl-cyanoacrylate, methoxypropyl-cyanoacrylate, methoxyisopropyl-cyanoacrylate, methoxybutyl-cyanoacrylate, propoxymethyl-cyanoacrylate, propoxyethyl -Cyanoacrylate, propoxypropyl-cyanoacrylate, butoxymethyl-cyanoacrylate, butoxyethyl-cyanoacrylate, butoxypropyl-cyano Acrylate, n-butyl acrylate, n-butyl acrylate, n-butyl acrylate, butoxy isopropyl acrylate, butoxy isopropyl acrylate, Ethoxyethyl-cyanoacrylate, 2- (2 '-methoxy) -ethoxyethyl-cyanoacrylate, 2- (2'- Cyanoacrylate, 2- (2'-butyloxy) -ethoxyethyl-cyanoacrylate, 2- (2'-pentyloxy) -ethoxyethyl- cyanoacrylate Acrylate, 2- (2'-hexyloxy) -ethoxyethyl-cyanoacrylate, 2- (2'-methoxy) -propyloxypropyl- Propyloxypropyl-cyanoacrylate, 2- (2'-pentyloxy) -propyloxypropyl-cyanoacrylate, 2- (2'-hexyl (2'-ethoxy) -butyloxybutyl cyanoacrylate, 2 (2'-methoxy) -butyloxybutyl cyanoacrylate, 2- - (2'-butyloxy) -butyloxybutyl-cyanoacrylate, 2- (3'-methoxy) -propyloxyethyl- cyanoacrylate, 2- (3'-methoxy) Cyanoacrylate, 2- (3'-methoxy) -butyloxypropyl-cyanoacrylate, 2- (3'-methoxy) Methoxy) -ethoxypropyl-cyanoacrylate, and 2- (2'-methoxy) -ethoxy, butyl-cyanoacrylate; (iii) an Ap / Po ratio that is miscible with the mixture of component (i) and component (ii) and is present in the composition in an amount from about 15 to about 40 weight percent of the composition, and ranges from about 1 to less than about 6 A specific cyanoacrylate composition is disclosed which comprises at least one plasticizer component comprising at least one ester group-containing plasticizer, but which does not contain pentaerythritol tetrabenzoate as the sole plasticizer.

The '278 patent teaches that a plasticizer in an amount of less than about 40 weight percent is used because a plasticizer in an amount of less than 12 weight percent does not achieve the required properties and a very high amount of plasticizer has a negative impact on the cure rate and bond strength , It is apparent that the required flexibility in the cured composition can be achieved.

Despite these efforts, there is a long-standing yet unmet need for achieving cyanoacrylates that maintain a certain degree of flexibility while exhibiting a more robust bond strength. It would therefore be highly advantageous to provide a solution to this need.

<Summary>

The present invention provides a cyanoacrylate-containing composition with improved torsional stress tolerance, particularly when combined with a plastic substrate, to overcome the disadvantage that bonding strength is compromised when improved flexibility of the cyanoacrylate composition is achieved.

More specifically, the present application is directed to a composition comprising a cyanoacrylate component based on a combination of ethyl-2-cyanoacrylate and octyl-2-cyanoacrylate, with from about 5 weight percent to about 12 weight percent acetyl tri A cyanoacrylate-containing composition having acetyl citrate is provided.

Also provided herein is a method of bonding plastic substrates together using a cyanoacrylate composition that exhibits improved performance when applied to torsional deformations. In fact, performance is improved to such an extent that substrate failure, not adhesion failure or adhesion failure, of the cured cyanoacrylate composition / substrate interface is observed.

The method comprises adding from about 5 weight percent to about 12 weight percent acetyl triacetyl citrate together with a cyanoacrylate component based on a combination of ethyl-2-cyanoacrylate and octyl-2-cyanoacrylate To provide a cyanoacrylate-containing composition; Providing at least one plastic part to be joined together; Comprising applying a cyanoacrylate-containing composition to at least a portion of the surface of the part (s) to be joined, and maintaining the cyanoacrylate-containing composition for a time sufficient to form the applied part.

The present invention also relates to the reaction product of the composition of the present invention.

The present invention also relates to a process for preparing the composition of the present invention.

The present invention will be better understood upon reading the section entitled "Detailed Description" below.

Figure 1 shows an X-Y plot of the tensile strength of the tube / connector assembly using the cyanoacrylate compositions shown in Tables 1 and 2 before and after the torsional stress was applied at 40 rpm.

<Detailed Description>

As described above, the present invention relates to cyanoacrylate-containing compositions that provide improved torsional stress tolerance, particularly when cured, when bonded to a plastic substrate.

The cyanoacrylate component comprises a combination of ethyl-2-cyanoacrylate and octyl-2-cyanoacrylate. The relative amount of octyl cyanoacrylate is from about 15 weight percent to about 50 weight percent, such as from about 20 weight percent to about 45 weight percent, preferably from about 28 weight percent to about 44 weight percent. Ethyl cyanoacrylate should be used as the balance of the cyanoacrylate component.

The cyanoacrylate component should be included in the composition in an amount within a range from greater than about 85 weight percent to about 95 weight percent, preferably from about 90 weight percent to about 93 weight percent of the total composition.

Acetyl triethyl citrate should be used in an amount of from about 5 weight percent to less than about 15 weight percent, such as from about 5 to about 12 weight percent.

Octyl cyanoacrylate and acetyl triethyl citrate should be included in the composition in amounts of from about 30 weight percent to about 65 weight percent, such as from about 40 weight percent to about 55 weight percent.

Any one or more selected from accelerators such as, for example, calixarenes, oxalicylenes, sila crown, crown ethers, cyclodextrins, poly (ethylene glycol) di (meth) acrylates, ethoxylated hydric compounds, May be included in the cyanoacrylate composition.

Many of these are known and are described in patent literature. For example, U.S. Pat. Reference is made to patents 4,556,700, 4,622,414, 4,636,539, 4,695,615, 4,718,966 and 4,855,461, the disclosures of each of which are expressly incorporated herein by reference.

For example, with regard to calixarenes, the following structures are useful herein:

Wherein R &lt; ¹ &gt; is alkyl, alkoxy, substituted alkyl or substituted alkoxy; R ² is H or alkyl; n is 4, 6 or 8;

One particularly preferred calixarene is tetrabutyltetra [2-ethoxy-2-oxoethoxy] calix-4-allene.

Numerous crown ethers are known. Examples which may be used individually or in combination herein include, for example, 15-crown-5,18-crown-6, dibenzo-18-crown-6, benzo-15- Crown-6, dibenzo-14-crown-4, dicyclohexyl-18-crown-6, Crown-8, cyclohexyl-12-crown-4, 1,2-decalyl-15-crown-5, 1,2-naphtho-15-crown- , 5-naphthyl-16-crown-5, 1,2-methyl-benzo-18-crown-6,1,2-methylbenzo-5,6-methylbenzo-18- crown-6, 1,2-vinylbenzo-15-crown-5, 1,2-vinylbenzo-18-crown-6, 1,2-t- butyl-cyclohexyl- -6, asym-dibenzo-22-crown-6 and 1,2-benzo-1,4-benzo-5-oxigen-20-crown-7. U.S.A. No. 4,837,260 (Sato), the disclosure of which is expressly incorporated herein by reference.

Many of the sila crowns are also known and are documented in the literature.

Specific examples of silacrown compounds useful in the composition of the present invention include

Dimethylsilyl-11-crown-4;

Dimethylsilyl-14-crown-5; And

Dimethylsilyl-17-crown-6

.

For example, U.S. Pat. No. 4,906,317 (Liu), the disclosures of which are hereby expressly incorporated by reference.

A number of cyclodextrins may be used in connection with the present invention. For example, as hydroxyl group derivatives of [alpha], [beta], [gamma] -cyclodextrin, those disclosed in U.S. Pat. No. 5,312,864 (Wenz), which will be suitable for selection as the accelerator component.

For example, poly (ethylene glycol) di (meth) acrylates suitable for use herein include those having the structure:

Where n is in the range of more than 3, such as in the range of 3 to 12, particularly preferably n is 9. More specific examples include PEG 200 DMA (where n is about 4), PEG 400 DMA (where n is about 9), PEG 600 DMA (where n is about 14), and PEG 800 DMA where n is about 19 , Where the number (e.g., 400) represents the average molecular weight of the glycol portion of the molecule, excluding the two methacrylate groups, expressed as grams / mole (i.e., 400 g / mol). A particularly preferred PEG DMA is PEG 400 DMA.

Among the ethoxylated hydric compounds (or ethoxylated fatty alcohols that may be used), suitable ones can be selected from those of the following structures.

Wherein _m is an integer from 1 to 30, such as from 5 to 20, n is an integer from 2 to 30, such as from 5 to 15, and R is H or alkyl , Such as C _1-6 alkyl.

When the accelerator contained by the structure is used, the accelerator is present in the composition in the range of from about 0.01 weight percent to about 10 weight percent of the total composition, preferably in the range of from about 0.1 weight percent to about 0.5 weight percent, Should be included in an amount of about 0.4 weight percent.

Stabilizer packages are also commonly found in cyanoacrylate compositions. The stabilizer package may comprise one or more free radical stabilizers and anionic stabilizers, the identity and amount of each of which is well known to those of ordinary skill in the art. For example, U.S. Pat. See U.S. Patent Nos. 5,530,037 and 6,607,632, the disclosures of each of which are incorporated herein by reference.

Other additives may be included in the cyanoacrylate compositions of the present invention, such as certain acidic materials (e.g., citric acid), thixotropic or gelling agents, thickeners, dyes, and combinations thereof.

In another aspect of the present invention there is provided a method of forming a substrate comprising applying two compositions onto a substrate, comprising applying the composition as described above to at least one of the substrates and then mating the substrates together for a time sufficient to allow the adhesive to adhere A method of bonding together is provided. In many applications, the substrate should be fixed by the composition of the present invention in less than about 150 seconds, and in some embodiments, in about 30 seconds, depending on the substrate.

In another aspect of the invention, a cured product of the composition as described is provided.

The present invention will be illustrated in detail by the following examples.

<Examples>

Compound

The cyanoacrylate compositions were prepared from the components listed in Table 1 below in recorded amounts. For comparison purposes, LOCTITE 401, Loctite 435 and Loctite 4851 were also included in the table.

* Toughened rubber with improved stability and peel strength

Each of the samples A to F, Loctite 401, Loctite 435 and Loctite 4851 was applied to a tube made of PVC and a plastic connector (i.e., polyvinyl chloride, polycarbonate, or ABS) was attached thereto. The bonded assembly was allowed to cure for at least 24 hours at room temperature prior to testing.

A pressure test was performed on the leaks on the combined pipe / connector (the assembly was immersed in water to observe any bubbles under pressure of about 20 psi). Traction tests were evaluated before and after applying torsional stress on the assembly. The achieved tensile strength was measured using an Instron instrument. Torsional stress was achieved using an assembly attached to a chuck that had an operational rotation for 15 seconds at 40 rpm.

In Table 2 below, the PVC tubing / PVC connector assemblies bonded by Samples A and C failed pressure testing after torsional stresses were applied, suggesting that leaks were observed. Leaks were also observed for assemblies joined by three commercial controls before and after torsional stresses were applied. The assemblies bound by samples B, D, E and F passed the pressure test for leakage. In addition, in the case of assemblies bound by samples B, D and E, better tensile strength was observed (before and after stressing) compared to the three commercial controls and other formulations. See also Figure 1 for a bar graph showing the tensile strength of these various samples. Failure modes after traction test are listed in Table 2.

-: Adhesion failure

+: Description failed

Table 3 below shows the tensile strengths of aged PVC tube / PVC connector assemblies, where samples B, D, E and F were used to bond the assemblies. More specifically, as with the samples recorded in Table 2, each of the four samples was applied to a tube made of PVC, and a connector made of PVC was attached thereto. A duplicate of five samples was prepared and evaluated for each sample. A set of assemblies was exposed to a temperature of about 60 DEG C for the time indicated and then the tensile strength was determined by applying a force to opposite ends of the assembly to laterally release the components.

As shown in the following Table 3, the intensities held between the initial measurements in the case of samples B, D and E and the measurements after thermal aging at 60 DEG C for 3 weeks and 6 weeks respectively were the same heat Significantly increased compared to the retained strength after aging evaluation. Thus, Sample F performed well, but adhesion failure was observed under aging conditions.

Tables 4 and 5 below show the pressure and traction test results formed on the PVC tube / PC connector and PVC tube / ABS connector assembly assembled by Samples B, C and D and three commercial controls. The data recorded in Tables 4 and 5 illustrate that excellent tensile strength can be obtained by using Samples B and D (both before and after applying a torsional stress). The assemblies bound by Samples B and D also exhibited better performance during pressure testing (at least in terms of leakage) than Sample C and the three commercial controls.

As shown in this example, the combination of octyl cyanoacrylate and acetyl triethyl citrate in ethyl cyanoacrylate is particularly preferred when the amount of acetyl triethyl citrate is less than about 5 weight percent to less than about 15 weight percent, Such as about 12 weight percent, and the amount of octyl cyanoacrylate is from about 15 weight percent to about 50 weight percent, such as from about 20 weight percent to about 45 weight percent, exhibiting improved torsional stress tolerance.

Claims (12)

(a) a cyanoacrylate component comprising a combination of ethyl-2-cyanoacrylate and octyl-2-cyanoacrylate; And
(b) from about 5 weight percent to less than about 15 weight percent acetyl triethyl citrate
&Lt; / RTI &gt; The composition of claim 1, further comprising a stabilizing amount of an acidic stabilizer and a free radical inhibitor. The composition of claim 1, further comprising a promoter component. 4. The composition of claim 3, wherein the accelerator component is selected from the group consisting of calicyl selenium, oxacaric selenium, sila crown, cyclodextrin, crown ether, poly (ethylene glycol) di (meth) acrylate, ethoxylated hydric compounds, &Lt; / RTI &gt; 5. The process according to claim 4 wherein the crown ether is selected from the group consisting of 15-crown-5, 18-crown-6, dibenzo-18- crown-6, benzo-15- crown- Crown-6, dibenzo-14-crown-4, dicyclohexyl-18-crown-6, dicyclohexyl-24 -Crown-8, cyclohexyl-12-crown-4, 1,2-decalyl-15-crown-5, 1,2-naphtho-15-crown-5, 3,4,5-naphthyl- -Crown-5, 1,2-methyl-benzo-18-crown-6,1,2-methylbenzo-5,6-methylbenzo-18- Vinylbenzo-15-crown-5, 1,2-vinylbenzo-18-crown-6, 1,2-t- butyl- cyclohexyl-18- crown-6, asym-dibenzo -22-crown-6, and 1,2-benzo-1,4-benzo-5-oxigen-20-crown-7 and combinations thereof. The composition of claim 1, further comprising an additive selected from the group consisting of a toughening agent, an impact resistant additive, a thixotropic agent, a thickener, a dye, and combinations thereof. A reaction product of the composition according to claim 1. Applying the cyanoacrylate-containing composition of claim 1 to at least one of the substrates; and
Mating the substrates together for a time sufficient to allow the adhesive to adhere
&Lt; / RTI &gt; wherein the two substrates are made of a thermoplastic material. Providing a cyanoacrylate component comprising a combination of ethyl-2-cyanoacrylate and octyl-2-cyanoacrylate,
Adding thereto an amount of acetyl triethyl citrate of less than about 5 weight percent to less than about 15 weight percent to form a cyanoacrylate composition, and
Providing two or more substrates having surfaces that can be mated,
Thereafter, at least one of the surfaces of the substrate made of a thermoplastic material is subjected to an interlocking process, using the cyanoacrylate composition therebetween, to form an assembly, and
Exposing the assembly to a torsional stress for a predetermined period of time
&Lt; / RTI &gt; wherein the cured product is a cured product. The composition of claim 1, wherein the acetyl triethyl citrate is present in an amount from about 5 weight percent to about 12 weight percent. The composition of claim 1, wherein octyl cyanoacrylate and acetyl triethyl citrate must be present in an amount in the range of about 30 weight percent to about 65 weight percent. 4. The composition of claim 1, wherein octyl cyanoacrylate and acetyl triethyl citrate must be present together in an amount ranging from about 40 weight percent to about 55 weight percent.

Images